GM recently made waves for claiming that its new electric Volt[1] gets 230 mpg[2], but the magic number seems more like 40. That’s because miles per gallon really only matter when a gas engine combusts. The Volt on the other hand will go around 40 miles on its electric battery before switching over to gas. If customers drive less than 40 miles per day, and if GM keeps the price under $40K (plus a $7,500 federal tax credit), many Americans could find themselves getting unlimited mpg for whatever it costs to plug in. So can GM really claim that the vehicle gets 230mpg? That’s where public debate[3] heats up.

Photo credit: AP Photo

Do professional test drivers accurately reflect real driving results? Will typical city drivers get “infinity” mpg if they don’t burn any gas? Are kilowatt-hours (kWh) a better standard than mpg for electric vehicles? And if an electric generating plant uses so many gallons to produce kilowatts for recharging batteries, doesn’t that just shift the overall carbon emissions to another sector (albeit one that is more energy efficient and easier to regulate)?

As a newer “series” hybrid, the Volt uses gasoline to power the motor when the battery runs low, rather than spin the wheels like a Prius[4] and other “parallel” hybrids. This feature boosts both the energy efficiency and the potential range (up to 400 miles for the Volt) of the vehicle.

As we approach more “pure” electric vehicles using less and less gas, the battery itself takes center stage. The Volt’s battery pack uses lithium-ion[5] technology to hold more energy per unit weight, as compared to current hybrid batteries using nickel-metal hydride[6]. In an interview on GM-Volt.com[7], GM’s Director of EVs and Hybrids Bob Kruse likens the evolution of electric car batteries to that of cell phones, and acknowledges a dynamic balancing act between technology, cost and people’s “range anxiety” over how far they can go on a single charge.

Customers want cars that look nice, too, and the Volt’s design teams appear to keep this in mind. If GM can keep moving forward with an appealing look for an affordable price, the Chevy Volt may very well plug into America’s emerging mix of alternative energy and transportation.